Well slotter



Nov. 7, 1939.

' c. P. BowlE WELL SLOTTER- Filed May 17, 1937 7 @awww A TT ORNEYS.

Patented Nov. 7, 1939 UNITED STATES PATENT OFFICE 9 Claims.

The present invention relates to apparatus for increasing the effectiveproducing area of a drilled well.

The principal object of the invention is to provide an apparatus whichis capable of being lowered into a drilled well, and which can beoperated from the surface, to cut slots in the formation into or throughwhich the well has been drilled. The slots are vertical and extend outradially from the well, and there may be as many such slots cut, one ata time, as is desired. Each slot greatly increases the exposed area ofthe formation, from which the fluid may exude. Some wells which, whendrilled in the ordinary way as cylindrical holes, produce comparativelyr little fluid because of certain adverse conditions of undergroundstructure or pressure, can be greatly improved by increasing theireffective area and thereby securing greater production. By cutting aplurality of narrow slots in the fornation, instead of reamng it outinto an enlarged cylindrical chamber, the exposed area is greatlyincreased, without the danger of destructive caving.

A second object of the invention is to provide an apparatus for thepurpose described above which is simple and rugged in construction andeasy to operate, and which requires only one source of power or powertransmitting connection to provide both its cutting and feedingmovements. Other objects and advantages of the invention will beapparent from the following description, which should be read with theun\ derstanding that changes, within the scope of the claims heretoappended, may be made in the form, construction and arrangement of theseveral parts herein shown and described.

A preferred embodiment of the invention is illustrated in theaccompanying drawing, in

which Fig. l is a vertical section showing the device in position in thewell.

Fig. 2 is a vertical section taken at right angles to the plane of Fig.1.

The apparatus requires suitable means for locating or orienting it inthe well and holding it securely in position, and suitable driving meansfor supplying the cutting and feeding power. These holding and drivingmeans may be located either in the well in proximity to the apparatusitself, or at the Surface and connected with the apparatus by strings oftubing. The latter arrangement is shown in the drawing, the referencenumeral II indicating a string of tubing to which the apparatus isattached and by which it is lowered or raised and held in position, andI2 indicating a smaller string of either tubing or rods which arerotated to provide the power. The means at the surface for holding thestring Il and rotating the string I2 are not shown.

(CI. Z55-1) The drive tubing I2 has a bevel pinion I3 secured to itslower end, which meshes with a gear I4 secured upon a horizontal shaftI5 mounted in the supporting tubing Il. Chains I6 connect said shaft I5with a second horizontal shaft I1, on which is a sprocket I8. Suitablesupport must be provided for the bevel pinion I3, such as a spider I9which provides a journal for the lower' end of the tubing I2.

The diameter of the supporting tubing II is reduced below the shaft I1.Within this reduced portion isa vertically slidable extension 20, whichvis prevented from rotating by a guide pin 2l and slot 22. 'I'he lowerend of said extension is enlarged, flattened and slotted, as shown at23, and carries a horizontal spindle 24, upon which an idler sprocket 25iS mounted in the slot of said end 23. The spindle 24 also serves as apivot for the forked upper end 26 of an arm 21, said arm extendingdownwardly and having an idler sprocket 28 mounted in its forked lowerend 29.

A flexible endless cutter in the form of a chain 30, having spacedprojecting teeth 3|, operates over the sprockets I8, 25 and 28. Whenthefdrive tubing I2 is rotated in such a manner as to cause the lefthand run of the chain to move upwardly, the pull of said chain willswing the arm 21 to the left (Fig. 1). The teeth 3| will, therefore, diginto the left .hand side of the well, cutting a narrow slot in theformation. This continues as long as the drive tubing is rotated, thechain pulling up on the lower sprocket 28 and swinging the arm 21 moreand more to the left as the cutting progresses. At the same time, theextension 20, carrying the sprocket 25, moves down to keep the chaintight. A spring 32 may be provided if necessary to assist the weight ofthe extension 20 to force the sprocket 25 down.

When the device has reached the position shown in broken lines, the slotin the formation will have the shape shown by the dotted line 33. Thedrive tubing I2 is then raised sufficiently to disengage the bevel gearsI3 and I ll, after which the supporting tubing II is pulled up, vtherebystraightening out the chain and forcing the arm 21 back to verticalposition. The supporting tubing II is then turned to a new position andlowered again, whereupon a new slot can be cut. If necessary, the drivetubing I2 can be rotated in the reverse direction to help straighten outthe arm 21. A bearing plate 34 is provided upon the back of the fork 23,to keep the right hand run of the chain from rubbing against the side ofthe well opposite the slot.

A latch is provided to keep the extension 2|) in elevated position, andthereby to keep the chain straight and the arm 21 vertical, while themachine is being lowered into the well and while it is being turned fromone cutting position to another. As an example of such a latch, I havethe sprocket I8 rotates clock-wise, the hook 35 is disengaged from thekeeper 36, but when said sprocket is reversed, .the finger only is movedwithout affecting the hook.

As long as the keeper 36 is engaged by the hook 35, the extension 2U Visheld up, and the arm 21 has no tendency to swing away from its verticalposition. However, when the sprocket I8 begins to rotate in the cuttingdirection, the hook is released, thereby allowing the extension 20V todrop down as soon as the arm 21 swings out.

The hook and keeper are provided with inclinedfaces as shown, so thatthey -automatically engage When the extension 2D is raised by thestraightening out of the chain.

The machine is illustrated as operating below the bottom of the wellcasing, which is shown at 4|. It is entirely possible, however, thatwith` cutters 3| of the proper material, the slots could `be cut throughthe casing. Thus the machine can be operated at any point in the depthof the well.

It will be seen that the cutting means, i. e., the chain, 30 isself-feeding. The same power, applied through the rotating tubing I2,not only moves the chain linearly but also, on account of the pivotalmounting of the arm 2l, causes the cutting run of said chain to swingout and feed itself laterally and upwardly into the formation. Thus onlyone power connection is necessary, outside of that for raising, loweringand holding the entire machine.

It will also be seen that, when the device is in inoperative positionthe cutter chain forms an elongated loop with substantially verticalparallel side runs, and the three supporting sprockets I8, 25 and 28 aresubstantially in vertical alignment, thus enabling the machine to belowered into the well. The cutting movement of the chain, however, pullssaid supporting sprockets out of alignment, and causes the side runs ofthe chain to spread' apart into the form of a triangular loop, one ofsaid side runs being forced against ethe side wall of the well to cut aslot therein.

I claim:

1. A well slotter. comprising a body capable of being lowered into awell, a flexible endless cutter carried by said body, said cutter havingtwo subsaid cutter when inoperative in the form of anV elongated loopwith susbtantially vertical side runs, and driving means for moving saidcutter, the force exerted by saiddriving means 'causing the side runs ofsaid cutter to spread apart so,

that vat leastc one of said runs will cut into the wall of thc well.

3. A well slotter comprising a body capable of being lowered into awell, a flexible endless cutter, movably connected supporting memberstherefor Afin-` positioned to hold said cutter when inoperative in theform of an elongated loop with substantially vertical side runs, drivingmeans for moving said cutter, the force exerted by said driving lmeanscausing the side runs of said cutter to moving said cutter, the forceexerted by said driv-l ing means causing the side runs of said cutter tospread apart so that at least one of said runs will cut into the Wall ofthe Well, and the movement of said cutter releasing said locking meansto permit said supporting members to follow the spreading movement ofsaid cutter, thereby keeping the loop thereof tight.

5. A well slotter comprising a body capable of being lowered into awell, a flexible endless cutter carried by said body, means for movingsaid cutter, a plurality of supporting means over which said cutterruns, said supporting means being substantially in vertical alignment tomaintain the cutter in the form of an elongated loop with susbtantiallyvertical side runs when inoperative, and said supporting means beingmovable out of vertical alignment to spread the side runs of said cutterapart to cause at least one of them to cut into the wall of the well.

6. A Well slotter comprising a pair of movably connected body sections,a iiexible endless cutter passing around said sections, said cutterhaving the form of a vertically elongated loop and said sections beingin substantial alignment when in inoperative position, said sectionsbeing movable out of alignment to spread the loop of said cutterlaterally to cause it to cut into a wall of the well, and means formoving said cutter.

7. A well slotter comprising a body capable of being lowered into aWell, a ilexible endless cutter carried by said body, said cutter beingin the form of a loop with two substantially vertical runs, means formoving said cutter, and means for changing the shape of said loop tospread said runs apart and cause one of them to cut a slot in the wallof the well.

8.`A well slotter comprising a body capable of being lowered'into awell, a iiexible endless cutter carried by said body, means for movingsaid cutter, a plurality of supporting means over which said cutter runsin the form of a loop, and means for changing the relative positions ofsaid supporting means to change the shape of the loop of said cutter.

9. A well slotter comprising a body capable of being lowered into awell, a vertically movable member carried by said body, a second memberpivotally connected with the first member for horizontal swingingmovement, a iiexible endless cutter, guiding means for said cutterrcarried by said body and said second member, said cutter causing saidsecond member to swing horizontally When said first member is movedvertically, and

means for moving said cutter.

CLIFFORD P. BOVVIE.

